From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Fri, 28 Apr 2017 13:25:33 -0400
Subject: [PATCH] NFSv4: Allow multiple connections to NFSv4.x (x>0) servers
Patch-mainline: Submitted, linux-nfs@vger.kernel.org
References: fate#322786

If the user specifies the -onconn=<number> mount option, and the transport
protocol is TCP, then set up <number> connections to the server. The
connections will all go to the same IP address.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/client.c           |    2 ++
 fs/nfs/internal.h         |    1 +
 fs/nfs/nfs4client.c       |   10 ++++++++--
 include/linux/nfs_fs_sb.h |    1 +
 4 files changed, 12 insertions(+), 2 deletions(-)

--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -180,6 +180,7 @@ struct nfs_client *nfs_alloc_client(cons
 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
 
 	clp->cl_proto = cl_init->proto;
+	clp->cl_nconnect = cl_init->nconnect;
 	clp->cl_net = get_net(cl_init->net);
 
 	cred = rpc_lookup_machine_cred("*");
@@ -498,6 +499,7 @@ int nfs_create_rpc_client(struct nfs_cli
 	struct rpc_create_args args = {
 		.net		= clp->cl_net,
 		.protocol	= clp->cl_proto,
+		.nconnect	= clp->cl_nconnect,
 		.address	= (struct sockaddr *)&clp->cl_addr,
 		.addrsize	= clp->cl_addrlen,
 		.timeout	= cl_init->timeparms,
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -78,6 +78,7 @@ struct nfs_client_initdata {
 	struct nfs_subversion *nfs_mod;
 	int proto;
 	u32 minorversion;
+	unsigned int nconnect;
 	struct net *net;
 	const struct rpc_timeout *timeparms;
 };
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -839,7 +839,8 @@ static int nfs4_set_client(struct nfs_se
 		const size_t addrlen,
 		const char *ip_addr,
 		int proto, const struct rpc_timeout *timeparms,
-		u32 minorversion, struct net *net)
+		u32 minorversion, unsigned int nconnect,
+		struct net *net)
 {
 	struct nfs_client_initdata cl_init = {
 		.hostname = hostname,
@@ -854,6 +855,8 @@ static int nfs4_set_client(struct nfs_se
 	};
 	struct nfs_client *clp;
 
+	if (minorversion > 0 && proto == XPRT_TRANSPORT_TCP)
+		cl_init.nconnect = nconnect;
 	if (server->flags & NFS_MOUNT_NORESVPORT)
 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
 	if (server->options & NFS_OPTION_MIGRATION)
@@ -1047,6 +1050,7 @@ static int nfs4_init_server(struct nfs_s
 			data->nfs_server.protocol,
 			&timeparms,
 			data->minorversion,
+			data->nfs_server.nconnect,
 			data->net);
 	if (error < 0)
 		return error;
@@ -1131,6 +1135,7 @@ struct nfs_server *nfs4_create_referral_
 				rpc_protocol(parent_server->client),
 				parent_server->client->cl_timeout,
 				parent_client->cl_mvops->minor_version,
+				parent_client->cl_nconnect,
 				parent_client->cl_net);
 	if (error < 0)
 		goto error;
@@ -1222,7 +1227,8 @@ int nfs4_update_server(struct nfs_server
 	nfs_server_remove_lists(server);
 	error = nfs4_set_client(server, hostname, sap, salen, buf,
 				clp->cl_proto, clnt->cl_timeout,
-				clp->cl_minorversion, net);
+				clp->cl_minorversion,
+				clp->cl_nconnect, net);
 	if (error != 0) {
 		nfs_server_insert_lists(server);
 		return error;
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -55,6 +55,7 @@ struct nfs_client {
 	struct nfs_subversion *	cl_nfs_mod;	/* pointer to nfs version module */
 
 	u32			cl_minorversion;/* NFSv4 minorversion */
+	unsigned int		cl_nconnect;	/* Number of connections */
 	struct rpc_cred		*cl_machine_cred;
 
 #if IS_ENABLED(CONFIG_NFS_V4)